This invention relates to a fluid system circuit board for interconnecting of fluidic and/or pneumatic components into a fluid circuit or system for controlling and separating of fluid devices.
Various controls and operating systems are constructed with electrical, hydraulic and pneumatic components as well as combinations of each components depending upon particular environmental and other design specifications. Electrical systems often are conveniently constructed with printed circuit boards with printed lines and certain small components for connection to other electrical components because of the manufacturing and operating advantages associated with such construction. Fluid systems, particularly pneumatic systems have many practical advantages in many applications. The development of fluidic amplifying and logic devices have further expanded the significance of fluid systems applications. Pneumatic systems are often employed because of the ready available sources, low cost and ease of exhaust to the environment. In control systems, the simplest and common construction connects the various components with individual tubing or lines. More recent designs have suggested suitable grooved plates interconnected to each other with suitable sealing gaskets therebetween to form an integrated assembly having conduits for connection of fluid components mounted to the assembly. The use of separate tubing is, of course, a relatively high labor intensive process, which is not only costly but further results in exposed conduits which are subject to damage, disengagement and the like. The latter disadvantage can be minimized by suitable potting of the system such as in a foam plastic, epoxy or the like. Potting, of course, is also an additional manufacturing step with attendant expense. The process also requires the additional provision of exhaust connections. Mechanically interconnected grooved plates with sealing gaskets therebetween minimized the labor cost. The reliability of the system, however, is directly related to the reliability and the life of the gasket material, the mechanical fasteners and the assembly. In many cases, the gasket material deteriorates with age and may also have certain relaxation characteristics, reducing the sealing characteristic with time. The fasteners should therefore be constructed to compensate for such changes. A more recent development has employed photoetched ceramic plates which are then permanently fired to form a single unit. Etching is a relatively expensive process, however, and the cost of such circuit boards are not particularly adapted for many high volume production applications which employ fluid components.
There is, therefore, a need for a simple and low cost fluid system circuit board and a practical production method of forming such board while maintaining a reliable and relatively long operating life.